Growth hormone releasing hormone (GHRH) is a peptide secreted by the hypothalamus. Normally, GHRH stimulates pituitary growth hormone release. The presence and activity of GHRH is therefore very important, particularly in normal growth and childhood development.
GHRH is also useful for testing pituitary function. Doses of GHRH can be used to stimulate pituitary secretion of growth hormone. If GHRH does not stimulate the pituitary to secrete growth hormone, this tends to indicate that the pituitary gland is not functioning properly.
GHRH can also be used to treat postmenopausal osteoporosis. Administration of GHRH can result in a reversal in bone mass loss in postmenopausal patients.
Because GHRH has many medical applications, it is highly desirable to be able to detect the presence or absence of GHRH in a sample or to qualitatively or quantitatively measure the activity of GHRH in a convenient, reliable manner.
Primary cultures of rat pituitary cells are typically used in a radioimmunoassay to asses the biological activity of GHRH. However, this radioimmunoassay is costly, time consuming and requires animals and radioactive materials.
A bioassay that would reduce the amount of time needed to detect GHRH in a sample would therefore be desirable. Additionally, it would be preferable if the bioassay did not require live animals, radioactive materials or specific antibodies.